[Plate XII]
Generally speaking, bowls like the one we are building may be decorated by one of three methods: By sinking lines or channels in its surface by means of a sharpened, chisel-like stick (D, [page 285]); by modelling or carving the surface; or by painting the surface with coloured "slip" or with coloured glaze. It should be explained that "slip" is a mixture of clay and water of the consistency of cream; it may be coloured or uncoloured. A combination of two or more of these methods is, of course, possible. Examples of the first two methods are shown in the illustrations of bowls, vases, and tiles. A combination of the first and third methods was used in decorating the tiles of the middle row shown in [Plate XIV opposite page 316].
Spacing in decoration
Classes of Decoration.—The form of the decoration is simply a matter of space division, as illustrated by two examples shown below. It is evident, too, that decoration, so far as form is concerned, divides itself naturally into three general classes: (a) The horizontal band; (b) the vertical division; (c) a combination of these two. The last will prove to be the most common of the three. It should be noted that an all-over pattern, which has been left out of consideration as tending to monotony, would commonly be a combination of both horizontal and vertical methods of division. It should be noted also that the presence of other than vertical and horizontal lines in pottery decoration does not affect the main classification. Typical examples of these divisions are illustrated in both bowls and vases, as well as in the cuts A and B. It will be seen in each case that one scheme or the other predominates and that there are possibilities for great variation in treatment.
Analyzing the patterns shown in all these illustrations, we find that the band or horizontal scheme offers a succession of large and small spaces, giving variety and rhythm. In many of those patterns showing the combination type there is a concentration or "knotting" of the line at regular intervals, frequently at the intersection of both horizontal and vertical elements. This is well illustrated by the left-hand bowl of the middle row shown in this plate opposite [page 294]. When the method of painted decoration is employed the concentration point is composed of mass instead of line. All this serves to give emphasis and rhythm.
For subject matter in decoration natural forms may be used as shown in the vase at the left of the top row illustrated in [Plate XIII, opposite page 312]. Or an abstract arrangement of lines may be employed, as shown in its nearest neighbour, which may or may not have had its origin in a very much conventionalized natural motif. The essential thing to remember is that the divisions of spaces must be varied and rhythmic and the decoration suited to the method of application.
How the Design is Applied to the Clay.—After the design has been studied as much as possible on paper it should be planned out on the bowl with a soft pencil, allowing sufficient space for the incised line or channel to be made. The clay should be leather-hard—i. e., stiff but not dry. The spacing around the circumference should be made exact, deviating somewhat, if necessary, from the spacing of the paper drawing. A good way to manage this important step in the process is to measure the circumference at the point of greatest width with a narrow strip of paper and then to divide this circumference by folding the paper evenly into the number of units desired. By wrapping the paper around the bowl again the points of division may be transferred to the clay and then projected upward or downward vertically to the belt that it is desired to meet. It is necessary to make sure that the vertical lines are true "meridians" and do not swerve to the right or the left. In order to test the horizontal lines, measurements may be made from top or bottom. All of this work is best done free-hand; for, aside from the value of the eye training derived, hand-built pottery is seldom exact enough to permit of a more mechanical method of planning its decoration.
The drawing on the clay having been completed, the next point is to choose the tool best fitted for the work and carefully make the cuts, deepening them from time to time as the work progresses. If the design is to be worked out in line, a chisel, like that illustrated in D ([page 285]), may be whittled from a pine stick. It is held nearly upright and used as a scraper to cut out at first a shallow channel. Reserve should be exercised in cutting, because, generally speaking, there is danger of making the design too insistent. Some of the best designs are very subtle and quiet. Care should be taken, however, to allow for a slight filling in of the hollow by the glaze when it is applied.